Search results for "Cyanate"
showing 10 items of 210 documents
Structural, spectral, and magnetic properties of end-to-end di-mu-thiocyanato-bridged polymeric complexes of Ni(II) and Co(II). X-ray crystal structu…
2002
Thiocyanatonickel(II) and thiocyanatocobalt(II) complexes of the composition Ni(NCS)(2)(HIm)(2) (1) and Co(NCS)(2)(HIm)(2) (2), where HIm = imidazole, were prepared and studied. In particular, the crystal structure of Ni(NCS)(2)(HIm)(2) was determined by X-ray methods. This compound crystallizes in the monoclinic system, space group P2(1)/n, with a = 7.720(1) A, b = 5.557(1) A, c = 13.774(3) A, beta = 102.54(3) degrees, and Z = 2. Its structure consists of a one-dimensional polymeric chain in which nickel(II) ions are bridged by two thiocyanate groups bonding in an end-to-end fashion in a trans arrangement. The Ni...Ni distance is 5.557(1) A. The crystal packing is determined by the intermo…
Uranyl Complexes of Alkyl-Bridged Ditopic Diaminotetraphenol Ligands and Their Use as Uranyl Ion Extractors
2013
The coordination chemistry of uranyl ions was studied using long n-alkyl chain (n = 5-8) bridged by N,N,N',N'-tetrakis(2-hydroxy-3-methyl-5-tert-butylbenzyl)diaminoalkanes (H4L1-H4L4) as ligands. All ligands formed 2:1 (U-to-L ratio) complexes with uranyl ions, but in addition 1:1 complexes could be characterized using ligands H4L2 and H4L3. The complexes were characterized by elemental analysis, spectroscopy (IR and NMR), and X-ray diffraction. The 2:1 complexes are of two types: [(UO2)2(H2Lm)(NO3)2(solvent)2] (m = 1 and 2; solvent = ethanol or propanol) or (cation)2[(UO2)2(H2Lm)(NO3)2(anion)2]·xsolvent (m = 2 and 4; cation = triethylammonium, anion = nitrate or thiocyanate, and solvent = …
Syntheses, crystal structures and magnetic properties of mono- and polynuclear [bis(2-arylcarbonyl)amidate]copper(II) complexes
2008
Abstract Five copper(II) complexes of formulas [Cu(bpcam)(CN)(H2O)] (1), [Cu(bpcam)(N3)(H2O)]2 (2), [Cu(bpcam)(NCS)(H2O)] (3), [Cu(bpcam)(dca)(H2O)]2 (4) and [Cu(bpca)(tcm)]n (5) [bpcam = bis(2-pyrimidylcarbonyl)amidate, bpca = bis(2-pyridylcarbonyl)amidate, dca = dicyanamide and tcm = tricyanomethanide] have been prepared and their structures determined by single crystal X-ray diffraction. Compounds 1 and 3 are mononuclear species where each copper atom is five coordinated with a tridentate bpcam and a terminally bound cyanide (1)/thiocyanate (3) ligands creating a basal plane with a water molecule in the axial position of a distorted square pyramid. Compound 2 is made of neutral di-μ-1,1-…
ChemInform Abstract: Oligosaccharide Synthesis via Electrophile-Induced Activation of Glycosyl-N-allylcarbamates.
2010
Abstract Glycosyl-N-allyl carbamates, obtained by reaction of anomerically unprotected saccharides with allyl isocyanate, can be activated by an electrophile-induced cyclisation and reacted with glycosyl acceptors to form the corresponding oligosaccharides By this method the mucin core 2 trisaccharide2 has successfully been synthesized. Due to the mild glycosylation conditions even 1-O-acetyl protected glycosyl acceptors can be used. This was demonstrated in the synthesis of a 1,6-linked glucosyl trisaccharide whereby a reptitious glycosylation strategy could be applied. 1. Dedicated to the memory of Professor Akira Hasegawa.
Über die cyclopolymerisation einiger bis-(N-vinyl)-verbindungen
1966
Durch Umsetzung von Vinylisocyanat mitAthylenglykol, Butandiol-1,4, Hexandiol-1,6, Octandiol-1,8, Brenzcatechin, Resorcin, Hydrochinon, cis- und trans-Chinit sowie Piperazin wurden die entsprechenden Bis-(N-vinyl)-Verbindungen hergestellt. Diese Monomeren werden unter gleichen Bedingungen radikalisch polymerisiert. Der Gehalt an seitenstandigen N-Vinylgruppen ergibt sich aus der bei saurer Hydrolyse gebildeten Menge Acetaldehyd. Der auf 0% Umsatz berechnete Doppelbindungsgehalt und damit der Cyclisierungsgrad hangt von der Struktur der Monomeren ab. Die Ergebnisse stimmen uberein mit der Ringbildungstendenz bei niedermolekularen Verbindungen (z. B. Ansaverbindungen) und werden an Hand von M…
Copolymers with ordered chemical structure
1984
Copolymers with well defined sequences can be obtained for instance by ring-opening polymerization of selected acetals. In this way regular copolymers of formaldehyde and ethylenoxide of the following structure are available2. In the same way some other copolymers with formaldehyde units were obtained. Of special interest are unsaturated polyacetales; for instance3 They can be modified by chemical reactions, for instance by hydrogenation, addition of bromine, iodine isocyanate or epoxidation. Recently a bicyclic unsaturated cycloacetal was prepared and polymerized4 Branched copolymers with a definite number of uniform sidechains are prepared by N-alkylation of polyamides5 The dependence of …
Potassium silver thiocyanate
2001
The structure of K[Ag(SCN)2] forms a three-dimensional network consisting of seven-coordinated K atoms and four-coordinated Ag atoms connected together by bridging thiocyanate groups.
Synthese von makromolekeln einheitlicher größe. II. Mitt. Synthese neuer diol-oligo-urethane nach dem duplikationsverfahren.
1955
Neue Diol-di- und Diol-hexa-urethane werden synthetisiert. Als Komponenten dienen aromatische Diisocyanate vom Arylen-, Diarylen- und Naphthylentyp und aliphatische Diisocyanate; als Diole werden Oligo-methylendiole, wie 1,4-Butandiol, und Diole mit Heteroatomen, wie Diglykol, N-Alkyldiathanolamine u. a. angewandt. Es werden besser losliche Oligo-urethane erhalten, die zur Durchfuhrung des Duplikationsverfahrens geeingeter sind. Es werden mehrere neue Diisocyanate hergestellt. Zur Charakterisierung der Diol-oligo-urethane werden bromsubstituierte Phenylisocyanate angewandt. New diol-di- and diol-hexa-urethanes are synthesized. Aromatic diisocyanates with arylen-, diarylen- and naphthylenstr…
Darstellung und eigenschaften von linearen oligourethanen mit phenylendgruppen und von cyclischen oligourethanen aus diäthylenglykol und hexamethylen…
1971
Es wurden lineare Oligourethane mit Phenylendgruppen und cyclische Oligourethane aus Diathylenglykol und Hexamethylendiisocyanat dargestellt. Der groste bisher isolierte Ring enthalt je sieben Grundbausteine und besitzt 119 Ringglieder bei einem Molekulargewicht von 1920. Eine gute Trennung der Oligomeren wurde durch Adsorptionssaulenchromatographie erzielt. Hierbei wurde ein Elutionsmittel mit Losungsmittelgradient verwendet. Schmelzpunkte, Umwandlungserscheinungen, Langperioden und Weitwinkeldiagramme der Oligomeren werden im Hinblick auf ihre Struktur diskutiert. Linear oligourethanes with phenylurethane endgroups and cyclic oligourethanes were prepared from diethylene glycol and hexamet…
H2-Antihistaminica, 1. Mitt.: 2-Substituierte 4-[[2-(N′-Methyl-thioureido)-äthylmercapto]-methyl]-imidazole
1976
Es wird die Synthese der 2-substituierten 4-[[2-(N′-Methylthioureido)-athylmercapto]-methyl]-imidazole 5a–f als potentielle H2-Antihistaminica beschrieben. Ausgehend von den Imidazol-4-carbinolen 3a–f lassen sich die 2-substituierten 4-[(2-Amino-athylmercapto)-methyl]-imidazole 4a–f durch saurekatalysierte Reaktion mit Cysteamin darstellen und mit Methylisothiocyanat in die entsprechenden Thioharnstoffderivate 5 uberfuhren. 2-Substituted 4-[[2-(N′-Methyl-thioureido)-ethylmercapto]-methyl]-imidazoles The synthesis of 2-substituted 4-[[2-(Ns′-methyl-thioureido)-ethylmercapto]-methyl]-imidazoles 5a–f, as potential H2-antihistaminics, is described. The acid catalyzed reaction of the imidazole-4…